Dies and punches for cutting and punching various material such as cardboard and plastic sheets are well known. Typical applications include mass production of display cards, instrument faces, semi-transparent film strips and backing materials. Typically a punch comprises a steel body having a work-engaging punch surface which is hollowed out to define a peripheral cutting edge and filled in the hollowed out portion with spongy material to eject the slug of punched material. These punches are relatively difficult and expensive to make, particularly in very small sizes.
A problem arises in the punching of holes in relatively rigid plastic sheets such as polycarbonates. These materials have a tendency to crack or spall during the punching operation and the application of conventional techniques has not been satisfactory.